Pump diaphragm



Dec. 1S, M28. 1,695,534

W. C. CARTER PUMP DIAPHRAGM Filed Feb. 27', 1925 )mL/AM` 6. CARTER BY ATTOHNEY Patented Dec. 18,(1928.

UNITED STATES PATENT oFFlcE.

WILLIAM CARTER, OF FLINT, MICHIGAN.-

PUMP DIAPHRAGM.

Application led '.Iiebruary 27, 1925. Serial No. 12,056.

` This invention relates to` diaphragm pumps, and has for its main object -to provide a diaphragm pump that can be operated continuously for a long period without liability of the diaphragm fatiguing or breaking down.

Another object is to provide a diaphragm pump that can be used successfully in a fuel supply system for internal combustion engmes for drawing gasolinefrom a source of supply and feeding it to the engine or to a device associated'wi'th the engine.

To this end I have devised a pump whose pumping element consists of a -diaphragm composed of a plurality of layers of fabric treated to render it impervious to the liquid being handled by the pump without 'making it stiff, brittle or iniiexible, and members arranged atopposite sides of said diaphragm for preventing it f rom being subjected to 20 =sharp bends or strains which tend to weaken p ture that it will not fatigue or break down when it is operated continuously'for long peiiods, as is necessary in a fuel supply pump for internal combustion engines. Accordingly, I have herein illustrated my inventionembodied in an lelectrically-operated pump designed for use on an` automobile orother power-operated vehicle,for drawing gasoline or other liquid fuel from a source of supply and feeding it to the engine or to the carburetor of the engine.

The figure of the drawing is a sectional -view of an electrically-operated diaphragm pump cgnstructed in accordancewith my invention.

Referring to the drawings, which illustrate one form ofthe invention, A designates the diaphragm of the pump which is composed of a plurali of layers m of fabric, preferably sea islan cotton, sail cloth or aeroplane cloth, that is treated so as to make it impervious to gasoline or water,- without making it stiff, brittle or inflexible. One process that I have found tobe very successful for treatthe fabric Afrom which the diaphrag'in'is made contemplates impregnating the fabric with a linseed oil solution that contains lamp black and a drier, and then drying the treated fabric in an oven. Any other treating process may be used, however, that will make the fabric impervious to liquids of the kind intended to be handled by the pump, without interfering with or destroying the inherent flexibility of the fabric. The diaphragm A is arranged in opposed relation to pumping chamber 2' and which may consist of a substantially cup-shaped casting or sheet metal stamping. The peripheral edge of the udiaphragm' A is combined with the member 1 in such a manner that the diaphragm is taut and normally disposed in subh a position that pressure exerted on the central portion ofthe diaphragm in one direction causes it to flex'away from the stationary wall 1 of the -a rigid member 1 that forms one wall of a pumping chamber, thereby creating a suction in said chamber which causes the liquid being pumped to be drawn into said chamber, and pressure exertedon the central portion of the diaphragm in the opposite direction causes it to'ilex towards the stationary Wall 1, thereby causing the liquid inthe pumping chamber 2 to be expelled from same. As previously stated, the diaphragm is a laminated structure composed of a plurality of layers of treated fabric, and in order to impart long life tothe diaphragm, the layers of fabric of which it is constructed are clamped together only at the center and at the peripheral edge of the diaphragm, thereby permitting the intermediate portions of said layers to' move relatively to each other when the diaphragm lexes back and forth.

In order to eliminate sharp bends in the diaphragm A and prevent said'diaphragm from being subjected toy strains or pressures that tend to disrupt it, I conne the central portion of the diaphragm between' two diskshaped members 3 and 4 whose edge portions are flaredin opposite directions so as to form I confine the peripheral edge portion of the vconvexed surfaces 3 and 4a, respectively` and l j diaphragm between the member 1, previously referred to, and an opposed clamping mem' ber 5, which members 1 and 5 are provided with convexed surfaces 1a and-5a, respectlve- 1y, that Hare in opposite directions from thev y point where the peripheral edge portion of the diaphragm is gripped by the members 1 and 5. The means that is used to actuate the. diaphragm is connected to the members 3 and 4, which embrace the center portion of the i wall 1 ofthe diaphragm, and when the pump is in operation, the movement of said members 3 and 4 away from and towards the stationary diaphragm to e brought into engagement, first 'with the convexed surfaces 3 and l at the right hand side of the diaphragm and then into e agement with the convexed surfaces 4 and 5 at the left hand side of the diaphragm. In this way the diaphragm is prevented from being subjected to sharp ends or strains which tend to injure or disrupt it, owine to the fact that the opposed convexed surfaces 3 and 4 on the members 3 and 4, respectively, constitute lsupporting surfaces for the diaphragm that eliminate strains on the diaphragm at the point where it is ripped by said members, and the convexe surfaces 1l and 5 on the members 1 and 5, respectively, constitute supporting surfaces for the diaphragm that eliminate strains on same adjacent 1 1e point where the diaphragm is gripped by the members 1 and 5. The area and curvature of the supporting surfaces just referred t0 can be varied, so long as said supporting surfaces are of such design and arrangement that they tend to impart a slight curvature to the diaphragm as it flexes back and forth and also support the diaphragm in such a way, when it is in its two extreme positions, that the strains to which the diaphragm is subjected at such times are not lconcentrated on the portions of the .diaphragm in immediate roximity to the members 3 and 4 that grip t e center portion of the diaphragm and the members 1 and 5 that grip the peripheral edge portion of the dia-` phracm. l I am aware of the fact that laminated pump diaphragms have heretofore been constructed from sheets of leather and rubber and from thin sheets of metal, but such laminated diaphragms cannot be used successfull in a pump employed for handling gasoline tliat forms 'part of a liquid fuel supply stem for an internal combustionv engmeg cause gasoline has an injurious effect on rubber and leather and the continuous flexing of the diaphra for lon periods causes the diaphragm to atigue an break down if it is constructed of materials of the. kind mentioned. M im roved'pump has neither of the objectlonab e characteristics above referred to and in numerous tests that have been made to determine the commercial practieability of my pump the diaphragm has shown no defects, even in destructive tests in which the diaphragm was operated continuously for periods far in excess of the normal life of a power-operated vehicle.

As previously stated, my broad idea conl `templates the use of any suitable means for actuating the dia hragm of the pump, such as an electrical y-operated mechanism, la spring, a mechanical device, or pressure propumping chamber causes they I diaphra m A is actuated by an electricall o )crate mechanism consisting of a solenoid t iat comprises a coil B, and a core composed l of a movable core piece or member C and a stationary core piece or member C. The members C and C are forced apart by an expansion s ring 6, and the movable core piece C is rigi connected to the members 3 and 4; that em race the central portion of the diaphragm. The coil B of the solenoid is surrounded by a metal housing D that encases the diaphragm clamping member 5, previously referred to, and said housing and diaphragm clamping member are provided with vcntilatimr openings 7 and 8, respectively, so as to cstitblish atmospheric pressure on the outside of the diaphragm A. lhe electric circuit that is used to energize said solcnoid is provided with two switches, one a manually-operated switch (not shown) that is adapted to be closed when it is desired to set the pump in operation, and the other an alitomaticalIy-operating, intermittent switch that opens and closes said circuit intermittently so as to cause the movable core'picee C to reciprocate, and thus actuate the diaphragm A. The intermittent switch just referred to is arranged inside of a removable cover or cap piece D on the end lWall of the housing D and comprises a stationary contact 9 and a movable contact 10. The stationary contact 9 is carried b an insulated member on the end Wall of the lousin r D that is electrically connected with one end of the coil B of the solenoid. The movable contact 10 is carried byfa member 11, herein illustrated as a lever, pivotally connected at 12 to a supportin device on the end wall of the housing and a apted to be rocked on its pivot so as to open and close the circuit in which the coil B is arranged; The contacts 9 and 10 are se arated to break the coil circuit by means o a hammer or circuit interrupter E arranged so that it will impart a sharp blow to the lever 11 which carries the movable contact 10 at or about the time the movable core piece C reaches the end of its inward stroke,

namely, the end of its stroke to the left. Duri ing the inward stroke of. said movable core piece ene'gy is stored up in a ring 13 that is combined with-the hammersl), and when the polarity of the magnetic force changes,

dueto the movable corepiece C coming in in which the contacts 9 and 10 are arranged consists 'of a rod 14 attached to the movable core piece C and having its outer end project ing through a hole in the .lever 11 and threaded so as to receive an adjustable'sto 15 that is arranged on the outside of the ever 11, said stop being adaptedto bear against said lever and move it towards the stationary contact 9 when the movable core piece C nears the end of its outward stroke, namely, the endof its stroke to the right. After the circuit of the solenoid has been closed, the movable core piece C will move inwardly towards the stationary core piecev C and the hammer E will be held in an inactive position, due to the .magnetic force produced by the current flowing through the core B of the solenoid.

,As soon as the movable core piece C comes into engagement with the stationary core piece C', the polarity of the magnetic force changes and immediately thereafter the hammer E will move outwardly under the influence of the spring 13 and strike the lever 11 a blow that separates the contacts 9 and 10,

' thereby opening the coil circuit. fAs soon as the circuit is opened or interrupted by' the blow imparted to the lever 11 by the hammer E, the movable ,core piece C moves outwardly under the influence ofthe spring 6 which was placed under tension by the inward stroke 'of said movable core piece, and at about the time said core piece C reaches the end of its outward stroke the stop 15 on the rod 14 causes the lever 11 to move into a position to vclose the coil circuit, whereupon the operations above described will be repeated. Accord-` ingly, so long as the manually-operated switch of the coil circuit is maintained in its closed position, the diaphragm A will Hex back, and forth and thus cause liquid fuelto be drawn into the pumping chamber 2, past the intake valve 16, and thereafter discharged fromV said chamber past lthe discharge valve 17, said valves being arranged in a valve passageway 18 that is connected by ports or ducts 19 with the umping chamber 2. avingthus described my invention, what I claim as new and desire to secure by Letters Patent is:

' 1. A laminated diaphragm composed of a plurality of layers of fabric treated with a linseed oil solution so as to render .said layers im rvious to lxiuids without making them sti brittle ori exible. k

2. A laminated dia hragm composed of a plurality of layers ofpfabrictreated to render it impervious to liquids without making the fabric inflexible, andmeanslfor clamping said layers together only at thecenter and at the peripheral portion of the diaphragm, thus leaving the intermediate portions of said layers free to move relatively to each other.

WILLIAM c. CAR'IEB.` 

